Abrasive body and method of making the same



Patented May 2, 1933 UNITED I \STATES PATENT OFFICE EMIL E NOVO'INY, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR To JOHN STOGDELL STOKES, 01 SPRING VALLEY FARMS, HUNTINGDON VALLEY P. 0., PENNSYLVANIA ABRASIVE BODY AND METHOD OF MAKING THE SAME No Drawing. Original application filed September 6, 1930, ,Serial No. 480,281. Divided and this application filed November 26, 1932. Serial No. 644,552.

This invention relates to thermosetting resinous products and the method of making the same, utilizing as an ingredient various natural resins of plant origin containing 5 phenolic tannols. Among resins of this class I may mention red and yellow gum accroides, gum benzoin and dra ons blood. My product comprises the admixture of various phenolic bodies or phenolic derivatives, preferably through preliminary reaction, in order to improve these natural resinous bodies to increase their preliminary fusibility, solubility, etc., and ultimately their strength, speed of cure, and ultimate complete infusibility.

This application is a division of my .application to Thermosetting lesinous roducts and method of making the same, erial No. 480,281, filed September 6, 1930.

These natural resins usually contain, when purchased in bulk, from 5 to 15% of more or less objectionable foreign matter such as sand and other gritty products which are extremely diiiicult to remove without altering the desirable properties of these resinous bodies. For most uses I find it highly desirable to eliminate this foreign matter, and I find it quite simple to do so inasmuch as the phenolic bodies such as phenol, cresol, xylenol,.etc. are good solvents for these natural gums and while in solution the gritty foreign matter may be removed as by settling, precipitation, centrifuging or filtration. While these gums are preferably but not necessarily in solution I may add suitable proportions of an aldehyde and/or an aldehyde derivative to combine with the phenol and natural gum to produce a potentially reactive resinous varnish, balsam, gum, or solid, hard, grindable resin.

These natural gums are reactive with and soluble in relatively water free aldehydes" such as furfural, benzaldehyde, .acetaldehyde, butyl aldehyde, etc., and the thermoreactivity of these resins is greatly increased while in the presence of these solvent aldehydic bodies. Impuritiesmay readily be removed while these gums are in solution, either While in a cold or warm state. The proportion of aldehyde added is not material inasmuch as any excess aldehyde may readily be caused to combine with any phenolic bodies which are preferably again added and a reaction caused to ensue to produce a product of liquid, semi-liquid, balsamlike or solid resinous nature.

The product is, furthermore, soluble and compatible with various aldehyde derivatives or polymers of aldehydes such as paraldehyde, furfuramid, furfur alcohol, triox methylene and hexamethylenetetramine. (3 f course, the dry aldehyde derivatives being solid bodies do not permit of removal of extraneous bodies as do the liquid bodies previously mentioned.

There is at this date considerable literature on these natural resins, such as British Patent No. 225,944, of December 15, 1924, to they British Thomson-Houston Co. Ltd., wherein it is disclosed that natural aromatic resins, as for example, acroides gum andbenzoin gum, can be rendered infusible or non-fusible by heating in the presence of formaldehyde. Molded compositions embodying my invention maybe made by mixing with the aromatic gum, a compound or derivative of formaldehyde, such for eX-' ample, as hexamethylene-tctramine. Similarly, the Chemistry of Natural and Synthetic Resins, by'Barry, Drummond & Morrell, published by D. Van Nostrand Co. 1926, wherein a discussion appears as'to the analysis and properties of gum accroides on pages 87 and 88. Also Rennie, Cook & Findlayson (translation Chem. Soc, 1920, 117, 338).-

The addition of 10% of hexamethylenetetramine to the accroides gum, as taught in .the British Patent No. 225,944 previously mentioned, Was followed by me under carefully controlled conditions. The hexamethylenetetramine was thoroughly ballmilled with the gum to provide as thorough a blend as possible and then mixed with, in parts by weight, wood flour 115, black dye 3, calcium stearate A to 100 parts of the gum-hexamethylenetetramine mixture. The mass was rolled on differential rolls, the hot roll heated to 310 F. and the cool roll heated to 210 F., and the rolling continued for a period'of 1% minutes. This composition produced a moldable plastic material which would cure to incomplete but ultimate infusibility without blistering when pulled hot from the die after a cure of 12 minutes and showed a flow of 3%. The product was so full of abrasive material as to be unusable in polished steel dies as the metallic. faces of' such dies would be badly scratched through these abrasive bodies which the gum originally contained.

A cure of 12 minutes is altogether too slow as it is essential that a good molding compound give a complete cure in at least 3 minutes. The product, furthermore, was incapable of going to complete infusibility. regardless of the length of time cured, and left a sticky, tacky substance on the surface of the molded part.

The flow of 3% is insufiicient for ordinary molding practice as it is necessary to have a relative flow of about 12% to pro vide a plastic mass capable of being molded under the usual pressures which are safe for polished, case hardened steel dies. By add: ing to these natural gums a quantity oi phenol, which may be done in any suitable mixing device or which may be worked in on the differential rolls as previously described, the reactivity of this product is increased very materially. For example, by the addition of only 10 parts of the weight of the resin in a phenolic body such as U. S. P. phenol crystals and without increasin the quantity of hexamethylenetetramine ca led for, I am enabled to decrease. the cure from 12 to 4 minutes and increase the flow from 3 to 9%. By increasing the proportion of phenol somewhat and, if necessary, 50 increasing the proportion of he'xamethylenetetramine I am enabled to further increase the flow and reactivity of the product.

I am likewise enabled to increase the cur-f ing time of these natural resins and improve the final infusible products so far as ultimate infus'ibility and strength are concerned through the addition of a quantity of potentially reactive synthetic resin which may be either of the single stage or which may have a hardening agent such as hexamethylenetetramine added thereto. The addition of at least an equal weight of such synthetic resin to such finely ground natural resin will provide an alloy having great- 85 ly improved flow in addition to becoming more reactive. The strength, likewise, of the product is increased to practically the same strength as products made of synthetic resins throughout. In other words, a molding compound made of gum accroides and hexamethylenetetramine in admixture with the fillers previously mentioned will show a tensile strength of only 3200 pounds to the square inch whereas a blend ofsynthetic resin and the gum accroides resin on the basis of equal parts by weight will show a tensile strength of approximately 5000 pounds to the square inch, or practically the same strength as the usual compounds now in use. l

Of course, the impurities present in the gum accroides product would make it out of the question to use such product in any. molding composition formed in highly polished molds or as is usually the case and, therefore, it is of utmost importance to either eliminate the abrasive tendency of these impurities or eliminate the impurities themselves.

I have found that by pulverizing the gum accroides resin and passing the pulverized product through a 200 mesh sieve, practically nothing but the gritty and woody substances will remain on top of the sieve to be discarded. Any pulverized, gritty ma- .terials have been reduced to a line powder and these, when admixed with fillers, other resins, etc., have little or no abrasive effect on the steel dies.

Preferably, however, I dissolve these natural gums-such as the gum accroides in a reactive solvent such as phenol or a phenolic body, and I may add to such solution an aldehyde capable of combining therewith, such as, for example, furfural, which further tends to lower the viscosity of the solution. I am then enabled to thoroughly strain or purify the solution, ridding the mass of all insoluble bodies. Thereupon I cause a reaction to ensue within the mass either by use of elevated temperatures or the use of suitable bases, acids, salts or other catalysts to produce a resinous body of such solution of natural gum and reactive liquid synthetic resinformmg ingredients. In the case of furfural, for example, the product is preferably heated in a jacketed still provided with a condenser forrefluxing and for distillation, and preferably I add from A; to 2% of the weight of the phenol used in a basic catalyst such as potassium, so-

dium or calcium carbonate. The product is refluxed for a period of one hour and then allowed to distill with the temperature rising to approximately 270 F.; and if a solid, grindable resin is required, and, of course, depending upon the amount of phenol and furfural added to the natural resin, the temperature may be allowed to reach 330'. R. The product may now be removed from the mo /i089 digester into suitable cooling pans ormay be cut with a suitable solvent such as an alcohol if a varnish is desired. To the solid resin, usually in agrinding operation, an

extra accelerating agent is added,-, such as some form of aldehyde or aldehyde derivative such as furfural, furfur alcohol, furfuramid, formaldehyde, trioxymethylene or hexamethylenetetramine. In the case of dry resins, it is preferable to use either trioxymethylene or hexamethylenetetramine as the hardening agent, and this may be used in from 2 to of the resin weight.

In reacting a mass of this type, using fur- 15 fural as-an aldehyde, it is to be understood that other aldehydes and other suitable cat alysts could be added, as for example, formaldehyde, to produce a product of either'a one or two stage resin. The'formaldehyde reaction being more energetic, lower temperatures may be used. This resinous product is either slowly reactive at elevated temperatures or else rapidly reactive, depending upon whether or not additional accelerating agents such as hexamethylenetetramine are added thereto.

There a slowly reactive product is to be made, the addition of a water free reactive aldehyde or aldehyde derivative such as furfural, furfur alcohol, etc. is very desirable inasmuch as the product is both a solvent and a hardening agent for these natural gums. It is then also possible to remove with greater ease insoluble impurities, etc. if this should be thought advantageous.

Although it is possible to admix the resin forming reagents with these natural gums, with or without additional hardening or accelerating agents, and, furthermore, although it is advantageous to add previously made synthetic resins of various types to these gum accroides products, it is to be understood that the highest reactivity and strength are obtained when such resin forming reagents are caused to react in the presence of these natural gums as in a suitable digester used by the makers of synthetic resins. As for example, a reaction .in the presence of gum accroides, phenol, furfural and potassium carbonate in such proportions as to yield approximately twice the Weight of resinous reaction product of the weight of gum accroides originally used will provide a synthetic resin curing in less than 3 minutes, and having a flow as high as 40%. In other words, instead of using only 115 parts of wood flour to 100 parts of resin,

it is possible to use with this mixture fully 200 parts of wood flour I have found it preferable to add to the 100 parts of this resin approximately 8.1 parts of hexamcthylenetetramine as under these conditions optimum-molding speed, cure and strength are obtained.

Wherein I have stated that I may use vagums, it is to be understood that these aldehydes can be used in excess of that ordinarily required to combine with such gum and that I may subsequently add a product such as urea orthiourea for the purpose of combining with such excess aldehyde such as, for example, the furfural or formaldehyde used, in order to produce an inexpensive, strong, tough material having ractically no phenol and aldehyde odor. T e natural gum itself has no phenol odor and is'really a sweet and pleasant smelling product when heated at high temperatures. If no phenol has been added, the difficulty of removing free phenol as where a tasteless, odorless synthetic resin is to be produced is eliminated. On the other hand, it is to be understood that for some purposes, it is advantageous to add both a phenol with an aldehyde in excess, in which i casethe inodorous aldehyde combining products such as the urea or thiourea can be combined subsequently.

For laminated workwhere varnishes are generally used it is essential that these natural gums be quite free from impurities and at the same time yield strong, tough products, and for certain purposes should have high plasticity, punchability, dielectric strength, and exhibit ease of punching when cold. For this purpose it is not always advisable to utilize a high percentage of phenol and, therefore, I prefer to proceed along somewhat different lines as, for example, I

dissolve these natural gums in only sufficient phenolic bodies such as the cresols and/ or xy-lenols to permit the filtration or removal of the impurities and to permit the ready admixture of such dissolved gum with a suitable aldehyde such as formaldehyde which is added in a sufficient quantity to act both asa combining agent with the phenolic body used and with the natural gum to be acted thereon. The product is refluxed for one to two hours with constant stirring, whenit will be found that the formaldehyde is thoroughly combined with both the phenolic body and .the natural resinous body and that a reaction has occurred between these ingredients, depending, of course, to some extent upon the type of catalyst used. 'So soon as the reaction is completed the excess water is distilled and a suitable solvent such as an ethyl or methyl alcohol is added thereto to provide a Varnish having the proper body. I have found for my purpose that it is best to provide a varnish for impregnation purposes utilizing these natural resins in combination with syn-- thetic resins having a viscosity of not less than 10 and not over 500 Sttirmer at 77 F. with the resin solvent at 52% in solution, in #5 completely denatured alcohol. Under these conditions of viscosity it is possible to secure impregnation and at the same tim e maintain a surface coating upon the sheet.

ters 40 precipitated therefrom and which 5 By this method I am enabled to produce a relatively clean, resinous product of increased solubility and reactivity, and convertible more completely when further heated either alone but preferably in the presence of hardl0 ening and accelerating agents to a final, hard,

set and infusible form. The product provides clean films and is, therefore, useful as a coating and impregnating varnish.

The resin is compatible with cellulose essuch as nitrocellulose and cellulose acetate and is, therefore, useful as a modifying resinoid or balsam for these products, greatly increasing the film strength, reducing the penetration of ultraviolet rays, improving 20 the weathering qualities or, in short, not only providing a greater solids content for the lacquers but at the same time greatly improving the flexibility, weathering resistance, etc., of such films.

In molding compositions I am enabled to produce either balsamlike bodies or solid, grindable, resinous products which may be mixed with suitable filling material of either an organic or inorganic nature and, for ordinary uses, preferably of a non-abrasive nature such as wood flour, tale, mica, asbestos, etc., but for special abrasive uses may be mixed with various natural or artificial abrasives such as are now used in the production of abrasive bodies such as wheels, discs, segments, sharpeningstones, etc. 7

By my method I am also enabled to provide a product which is more soluble in dilute alkalis, which may more readily be may therefore be conveniently incorporated as at the heaters or stuff chest of a paper mill with various fibrous bodies to. be incorporated therewith into paperlike sheets of any 4 desired thickness. These sheets may subsequently be pressed and. molded to any desired shape. I havefound this product to be quite valuable in the manufacture of various shock resisting shapes such as lamil nated sheetlike bodies. This converted natural resin'can be powdered to an extremely fine form and may in this condition be suspended in the beater or stuff chest liquors -either with or without the use of a suspensoid such as, for example, starch or other gelatinous material. It is, however, to be understood that I reserve the right to use these natural gums either in the form of previously reactedbodies with aldehydes or in the presence of phenolic bodies including added supplementary accelerating or hardening agents if desired.

It is my purpose to utilize these natural thermosetting resins either as starting raw materials for the production of useful,

. make a strong and ultimately infusible bodies for use as impregnatlng varnishes 1n the manuor modifying agents for various resinous -and non-resinous plastics, lacquers and varnishes; as modifying agents forsynthetic resins; as useful in the plastic molding art as various reaction and reactive products for hot or cold molding of mechanical and dielectric-bodies and for the production of self lubricating bearings, carbon brushes, and various abrasive and non-abrasive compositions and shapes.

I may combine or incorporate various liquid, semi-liquid or solid bodies having desirable technical properties such as colors, pigment, dyes, modifying agents, plasticizing bodies, solvents, etc., either prior to, during the conversion or thereafter, providing resinous alloys or compounds most suitable for the many diverse uses made of my modified natural resins.

For example, I can combine or incorporrale with my resins from 5% to 100% of rosin by heating the products to a temperature of from 150 1*. to. 350 F. to provide a useful gum for the varnish maker. I may substitute forthe rosin ester gum 01' by the addition of glycerine may produce the ester gum in situ. Similarly, I may add from 5 to 100% of china wood oil of the weight of the gum accroides or the like and heat the mass in a suitable heated digester either in the presence of added phenolic bodies and/or aldehydes 'to provide a balsam, gum-or resin useful for the lacquer and varnish maker. 7.

- For use in the making of hot or cold pressed abrasivewheels, I can coat the abrasive grain surfaces with a solvent such as furfural, or furfur alcohol and add thereto a pulverized gum accroides resin of either the natural form includinga hardening agent or else in its modified form after having been combined with phenol or an alde- The gum when cut with furfural, furfur alcohol or .other solvents to product having a specific viscosity of from 150 to 50$) Sttirmer at 77 F provides a sticky, tacky body capable of holding a sufiicient quantity of pulverized gum or synthetic resin including hardening agents, etc., to provide either a wet or dry granular mix moldable either in heated or cold molds.

These gums are compatible with urea and th iourea and will produceuseful alloys when combined in the presence ief a suitable quantity of an aldehyde such as formaldehyde or its polymers and derivatives.

Likewise, I can combine these gums in the presence of a trace of a mlneral acidsuch able alloy by combining therewith a polybasic acid such as phthalic anhydride and a polyhydric alcohol such as glycerine.

These natural gums will combine with small quantities of carbohydrates when heated in the presence of traces of mineral acids such as sulphuric and when first cut or dissolved in phenol about of the phenol weight in a carbohydrate in the presence of a trace of a mineral acid be combined to provide a modified resinous alloy having improved solubility and flow.

I have given previously general examples of the reactions most suitable for utilizing these natural resins through reactions with phenolic and aldehydic bodies, either in the presence or absence of catalysts, accelerators and/or hardening agents. examples are given to more clearly illustrate several methods that may be used as a basis for the production of new, valuable, potentially reactive resinous products.

Where I call-for gum accroides I prefer to use the red gum accroides of commerce but can use other natural gums of plant origin containing free phenolic hydroxyl oups.

The reactions are preferably carrled out in a closed copper lined digester provided with heating and cooling coils, a stirring device, a condenser for refluxing and distillation and necessary outlets and inlets. The digester is preferably heated with steam and cooled with water. i

The quantities given are all parts by weight.

Example No. 1

Phenol, U. S. P 50. Furfural 42.5 Gum accroides 35.

Heat to dissolve gum and strain to remove impurities. Add to clear product Potassium carbonate 0.75

Reflux but preferably distill through separator. In 2 4 hours of distillation through separator an end temperature of 310.F. is reached and a hard, grindable resin having a melting point approximately 310 F. is produced.

By a separator I mean a device capable of removing the water as soon as condensed from the distillate and of returning the condensed phenol, furfural and other reagents to the digester. A separatory funnel can be used instead as the reagents will settle to the bottom and may be frequently returned to the kettle. In principle, the device is a concentrator of the reactive reagents contained in the distillate and by rejecting the water a high end temperature is attained without counter pressure. This high temperature is required when furfural and other high boiling aldehydes are used as furfural starts to react in the presence of phenols A fewand gum accroides at 270 P. which is well over the boiling point of water.

This product is'slowly reactive and when a solvent such as alcohol, furfural or furfur alcohol is added can be used for various var nishes for coating and impregnation as is well understood. The speed of cure of the product can be increased by the addition of about 5 parts, moreor less, of hexamethylenetetramine to each 100 parts of the resin solids. The keeping qualities are poor when hexamethylenetetramlne is added and it is therefore. preferable to add this hardener when the varnish. or lacquer is to be used; otherwise, the product will go to arubbery mass in a month to six weeks at room temperatures.

This product also makes a strong, free flowing, hard resin for use in making various compounds when pulverized with 10% of the resin weight in hexamethylenetetramine. Speed of cure 3 minutes.

The speed of cure and strength can be further increased by adding to this mix 12% of the resin weight in a two stage phenol resin, preferably a phenol-formaldehyde product. Speed of cure 1 minutes. It will be of interest to state that under similar conditions a two stage phenol-furfural or formaldehyde resin made in the regular well known manner will show a speed of cure of 3 minutes, and a gum accroides resin with 10% of hexamethylenetetramine added as described in British Patent No. 225,944 will show a speed of cure of 12 minutes.

For pulverizing I prefer to grind in a ball mill to a fineness of 200 mesh.

Example N0. 2

flexibility and flow is provided, most use ful for coating and impregnating varnishes.

i Example No. 3'

A mixture of Gum accroides; 30. Phenol, U. S. P 25. Furfural 20.

Dissolve gum, strain and add Potassium carbonate 0.4375

React as in Example No. 1.

Melting point 234 F. Solubility good. When ground with 10% of resin weight of hexamethylenetetramine a cure of 3. minutes is attained but the flow is only 1%. Shows the need for a higher proportion of synthetic phenolic resinoids-to provide a product of good flow. A similar product but diff fering in these proportions as in Example 1 shows a flow of at least 50%.

Emample N0. .4

Monsanto duty free cresol and xylenoL- 24.

Furfural 16.

Gum accroides 16.

Dissolve gum, strain and add Potassium carbonate 0.36

React using separator as in Example No. 1, distilling through separator for approximately 1 hours, producing a sticky, tacky, balsamlike condensation product. Allow temperature to rise as volume of distillate decreases. Cool down to 180 F. and add Formaldehyde 10.

Boil under reflux for about a half hour,

Example N0. 5 A phenol, cresol or xylenol mixture 150.

Gum accroides 100. Dissolve, strain, filter or centrifuge. Add

Formaldehyde 100. Aqueous ammonia Reflux about to 1 hours, cooland decant from watery layer or distill under reduced pressure to reduce water,

Add preferably while warm Alcohol Heat until all in solution.

Reflux to provide a product having preferably a specific viscosity of from 20 tiiQOO Stiirmer at'77 F.

By cooling without the addition of a vent after distillation to remove occluded volatile materials a hard, grindable resin is provided. Both the varnish and resin are potentially reactive and ordinarily require no added hardening agents. Lubricants, plasticizers, etc., can be added in usual well known amounts.

Example No. 6

Phenol (Barretts crude No. 1) 50.

Red gum accroides 35.

Heat, dissolve, filter, add

Formaldehyde 35.

Sulphuric acid, U. S. P. 0.03

Reflux 2 hours. Distill until a hard, grindable resin having a melting point from 180 F. to 250 F. is obtained. Cool and grind in ball mill with 5 to 10% lime and 5 to 10% hexamethylenetetramine of the resin weight. Grind very fine. \Vhere a varnish is desired add solvent to warm kettle contents, omit lime; preferably add hexamethylenetetramine when product is to be used.

A very soluble resin of high reactivity. Makes good varnishes, molding compounds and abrasive wheel bonds.

Ewample No. '7 Phenol (Barrets crude No. 1) 50.

Gum accroides, red or yellow 35.

Heat, dissolve, filter and add Formaldehyde 35.

Phosphoric acid, U. S. P 2.

Reflux for about 2% hours. Distill to a melting point as given in Example No. 6 which is to be followed. Produces a light permanent and light colored, clear, resinous product.'

Ewample N 0. 8

Phenol 50.

Gum accroides 50.

Heat, dissolve, filter, cool and add Formaldehyde 75.

Heat to 130 F., stir well, and combine with free formaldehyde.

Dissolve in alcohol to 51% resin sol ds. An odorless, inexpensive varmsh for 1mpregnation into fillers or laminated cloth or paper. By omitting the solvent a dry, grindable, odorless resln 1s produced for ,compounding with venous fillers "as paper, cloth, wood flour, etc. A good bond for food containers, dental parts and abrasivezwheels 'for' dental use. Other phenolic bodies can be substituted for the phenol. Resorcinol produces a very fast curing product; xylenol a slow curing .resinoid. Example No. 9 Gum accroides ground and sieved to about 200 mesh, discarding the mater1a1 remain'ing on seive, consisting of hard grltty and "woody fibrous material. Thls elimi- Phosphoric nates foreign matter apt to scratch the dies or appear in the molded or coated article as a defectffl Ofthis ground and purified materiaL- 100 Hexamethylenetetramine 5 to 10 Grind in ball mill jor otherwise thoroughly coat and blend. l

This product can be used as a resin binder for various molding compounds. Used in. this way the gbjection to the impurlties is greatly minimlzed. The flow 1s low and curing speed is about 12 minutes. The

product is low priced and where low filler content is called for or where temperatures in excess of 350 F. are available a use can be found due to its low cost.

Example N0. 10

Gum accroides purified in Example 'No. 9 but without the added hexamethylenetetramine 30. A reactive synthetic resin 100.

' gum as the reactive resin, especially when of the phenol-formaldehyde type, will harden the gum to greater ultimate infusibility than if such gum is used alone with added hexamethylenetetramine. Flow better than either resin or gum alone. Cure time fairly rapid.

A varnish can be made therefrom through the use of solvents.

Example N0. 11

Gum accroides of Example 9 including hexamethylenetetramine 100. Reactive phenol-formaldehyde resin 12. 5

Grind and/or blend. Greatly improved cure, flow and solubility.

Example N 0. J2

Gum accroides, commercial": 100.

Dissolve, remove impurities in any desired manner. Add of gum weight, to hex amethylenetetramine and reflux in diges er for 2 hours or until a specific. viscosity at,- 55% gum solids at 77 F. is 40 to 90 Stormer. Add 5 to 10% of gum in further; hexamethylenetetramine when ready to use- When the added alcohol is distilled from the mass as under reduced atmospheric pressure a solid, clean, grindable resin results-E with the hardening agent substantially com-' bined therewith and useful for incorporation at the heaters or stuff chest of a paper mill into fibrous bodies and, if desired, in sheetlike form.

Additions of other synthetic resins, plasticizers, colors, fillers can be made at any time.- Useful for laminated work when blended with other synthetic resinous varnishes.

The addition of alkalis such as oxides and hydroxides, whether dry or in aqueous solution, has a marked tendency to increase the reactivity of these natural resins and, therefore the addition of such bodies in small amounts may at times be desirable.

The addition of say 5% of the resin weight in calcium oxide is quite beneficial.

These natural resins, furthermore, are

compatible with and soluble in urea and produce complex resinous condensation products when combined with a suflicient amount of formaldehyde to provide a product having little or no free urea. The reaction is advantageous inasmuch as the usual urea-formaldehyde resins such as are already well known in the art have no pro longed state of thermo-plasticity but follow rapidly from a liquid stage to a rubbery or solid stage. When, however, combined.

with purified resins of the gum accroides type the products become very plastic and therefore may be molded with ease. The manner of reacting these products does not matter so much so long as the reaction is carried on in accordance with prior 'art pertaining to the well known practice of combilling, formaldehyde and urea. The proportion of gum accroides used may be very small indeed, as I have found that only 5% of gum accroides thoroughly dis ersed in the urea-formaldehyde condensatlon product would giye a material having desirable flow. It is not well to use a high percentage because of the dark color of the accroides gum, but, of course, this is not objectionable it dark colored products are to be produced. Vhether the reaction is carried in situ, i. e., in the presence of the gum accroides or not, is really immaterial as it is 'just'as beneficial to incorporate this natural gum with a finely comminuted dry resinous condensation product or composition including fillers.

brace such products as the several "varieties.

of gum accroides, gum .benzoin and dragons blood of commerce.

p lVherein I have'claiined a phenolic body (P11182111 to include various homolog's or substitutedphenols and-various resinous con-' den'sa tion products-derived from phenol.- Amongefte phenols, for example, I would include among'other hom'ologs of phenol the crcsols, xyl'ehols, resorcinol, naphthols and mixtures ofthese. I I \Vherein I have described and claimed the use of furfural I mean to include any furane derivative which is -useful for my purpose such as, for example, fu'lfuramid or furfur alcohol or homologs 'of furfural such as, for example, ethyl or methyl furfural.

Wherein I have shown hexa or hexamethylenetetnamine I wish it to include oth- The statements with regard ,to the use of i or bodies containing reactive methylene groups in condition to comine with such resinous bodies such as, for example, formaldehyde in its various forms, paraformaldehyde, trioxymethylene, anhydroformaldehydeaniline or other resinous bodies having free active methylene groups.

It is to be understood that the examples givenherein are merely by way of illustration and that radical departures in procedure, proportion, reacting conditions, etc., may be made without departing from the spirit of this invention" or the scope of the appended claims.

The present application discloses subject matter not claimed herein, as the claims in this case are drawn specifically to the use of various phenolic bodies combined with these natural gums. Further divisional applications will be filed to cover other disclosures not claimed herein.

I claim:

1. An abrasive composition comprising abrasive grains, a natural resin of plant origin containing free phenolic hydroxyl groups and a hardening agent.

2. An abrasive composition comprising a natural resin of plant origin containing free phenolic hydroxyl groups, another phenolic body, a hardening agent and abrasive grains.

3. An abrasive composition comprising a natural resin of plant origin containing free phenolic hydroxyl groups having another phenolic body incorporated therewith, an aldehyde and abrasive grains.

4. An abrasive composition comprising a natural resin of plant origin containing free phenolic hydroxyl groups, a synthetic resin, a hardening agent and abrasive grains.

5. An abrasive composition comprising a natural resin of plant origin containing free phenolic hydroxyl groups, a synthetic resin produced therein and abrasive grains commingled therewith.

6. An abrasive composition comprisin a natural resin of plant origin containing ree phenolic hydroxyl groups, a synthetic resin produced in situ therewith, a hardening agent and abrasive grains.

7. An abrasive composition comprising a natural resin of plant origin containing free phenolic hydroxyl groups and hai ing incorporated resin forming ingredients and abrasive grains.

8. A composition for making abrasive implements comprising a natural resin of plant origin containing free phenolic hydroxyl groups, another resin incorporated therewith, a hardening agent and abrasive grains.

9. A composition for the making of abrasive implements comprising, a natural resin of plant origin containing free phenolic hydroxyl groups, an aldehyde and abrasive grains.

10. A composition for the making of ab.- rasive implements comprising, a natural resin of plant origin containing free phenolic hydroxyl groups, a hardening agent, a solvent and abrasive grains.

11. A composition for the making of abrasive implements comprising, a natural resin of plant origin containing free phenolic hydroxyl groups, another resin incorporated therewith, a solvent and hardening agent and abrasive grains.

12. A composition for the making of abrasive implements comprising, a natural resin of plant origin containing free phenolic hydroxyl groups, a polybasic acidpolyhydric alcohol product and abrasive grains.

13. A composition for the making of abrasive implements comprising, a natural resin of plant origin containing free phenolic hydroxyl groups, a polybasic acid-polyhydric alcohol product, a solvent and hardening agent and abrasive grains.

14. The herein described method of making a composition for making abrasive implements comprising the step of commingling abrasive grains with a potentially reactive natural resin of plant origin containing free phenolic hydroxyl groups.

15. The herein described method of making a composition for maln'ng abrasive implements comprising'the step of commmgling abrasive gains with a solution of a natural resin of plant origin containing free phenolic hydroxyl groups.

16. The herein described method of making a composition for making abrasive implements comprising the steps of commingling abrasive grains with a solution of a natural resin of plant origin containing free phenolic hydroxyl groups and then commingling a synthetic resin therewith.

17 A formed and heat hardened abrasive implement according to claim 1 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

18. A formed and heat hardened abrasive implement according to claim 2 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

19. A formed and heat hardened abrasive implement according to claim 3 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups. a

20. A formed and heat hardened abrasive implement according to claim 6 wherein maccroides is used as the'natural resin 5 of plant origin containing free phenolic hydroxyl groups.

21. A formed and heat hardened abrasive implement according to claim 7 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

22. A formed and heat hardened abrasive implement according to claim 8 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

23. A formed and heat hardened abrasive implement according to claim 9 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups. a

24. A formed and heat hardened abrasive implement according to claim 10 wherein gum accroides is used as the naturalresin of plant origin containing free prenolic hydroxyl groups. 25. A forme implement according to claim 11 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

26. A formed and heat hardened abrasive implement according to claim 12 wherein gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

27. A formed and heat hardened abrasive implement according to claim 13 wherein d and heat hardened abrasive" gum accroides is used as the natural resin of plant origin containing free phenolic hydroxyl groups.

28. The herein described method of making a formed and heat hardened abrasive implement formed from a composition comprising a natural gum of plant origin containing free phenolic hydroxyl groups reacted in the presence of a'phenolic, body. and an aldehyde and having incorporated therewith granular abrasive material to provide a potentially reactive moldable composition,

forming said composition and heat harden-i t t u f b1 1 M b d san1a yin usi e,1nsou e o y.

ing the same to a hard timate bonded body;

29. The herein described method ofni'aking a formed and heat hardened abrasive implement formed from a composition set and infusible u comprising a natural gum of plant origiri containing free phenolic hydroxyl groups repolyhydric alcohol product, incorporating a acted in the presence .of a phenolic body and an aldehyde derivative and having incorporated therewith granularabrasive material to provide a potentially reactive moldable composition, torming said composition and heat hardening the same to a hard, set and infusible body.

30. The herein described method of making an abrasive implement comprising a natural resinous product resulting from the reaction in the presence of a natural gum of plant origin containing free phenolic hy droxyl grou s of a phenolic body and an aldehyde, a ding said' resinous product to granular abrasive material, forming an abrasive implement therefrom and heat hardening said implement to a substantially infusible and ultimate form.

31. The herein described method of making a shaped and bonded ultimate form of abrasive article consisting of the steps of incorporating a natural resin of plant origin containing free. phenolic hydroxyl groups a hardening agent and a granular abrasive material, shaping said article and heating the shaped article to set and harden the bond.

32. The herein described method of making a shaped and bonded ultimate form of abrasive article consisting of the steps of incorporating a natural resin of plant origin containing free phenolic hydroxyl groups and a granular abrasive material, adding a potentially reactive synthetic resinous product, forming the composition into an-abrasive article and heating said article to pro- 1gihlle a substantially infusible, insoluble 3 The herein described method of making a shaped and bonded ultimate form ofabrasive article consisting of the steps of in corporating a natural resin of plant origin containing free phenolic hydroxyl groups with a. granular abrasive material, adding a potentially reactive'phenolic resin, forming the composition into an abrasive article and heating said article to provide a substantially infusible, insoluble body.

34. The herein described method of making a shaped and bonded ultimate form of abrasive article consisting of the steps of cornmingling a natural resin of plant origin containing free phenolic hydroxyl groups with a potentially reactive synthetic resinous product and a hardening agent,- incorporating a granular abrasive material, forming the product into an abrasive article, and heating said article to provide a sub- 35. The herein described method of making a shaped and bonded ultimate form of abrasive article consisting of the steps of conimingling a natural resin of plant origin containing free phenolic hydroxyl groups with a potentially reactive polybasic acidgranular abrasive material, forming the product into an abrasive article, and heating said article" to provide. a substantially infusible, insoluble body.

36. The herein described method of making a shaped and bonded ultimate form of origin containing free phenolic hydroxyl groups in a phenolic body, removing insoluble impurities from said solution,.adding an aldehyde to the solution, heating to cause 5 a reaction between said materials resulting in the formation of a new resinous product and incorporating a granular abrasive material with said resinous product and hardening the resinous product by further heating to cause it to become substantially infusible and act as a binder for said abrasive material to produce an abrasive implement.

38. The herein described process which comprises eliminating substantially all of the objectionable insoluble impurities from a natural resin of plant origin containing free phenolic hydroxyl groups, adding a potentially reactive synthetic resinous product and a hardening agent, incorporating a granular abrasive material with said materials, and hardening the resultant product by the action of heat to form an abrasive implement.

39. The herein described process which comprises dissolving a natural gum of plant origin containing free phenolic hydroxyl groups in a phenolic body, removing ob jectionable insoluble impurities from said solution, adding a hardening agent to said solution and heating to cause said ingredients to react to form a fusible but potentially reactive resinous product, incorporating a granular abrasive material with said res1nous product, pressing said materials to a predetermined shape and size and heating to harden the resin and form a relatively strong abrasive implement.

40. The herein described process which comprises dissolving a natural gum of plant origin containing free phenolic hydroxyl groups in a phenolic body and an aldehyde, removing ob ectionable insoluble impurities from said solution, heating to cause said ingredients to react to form a fusible but potentially reactive resinous product, incorporating a granular abrasive material with said resinous product, pressing said materials to a predetermined shape and size and heating to harden the resin and form a relatively strong abrasive implement.

41. The herein described process comprismg eliminating substantially all of the objectionable insoluble impurities -from a natural gum of plant origin containing free phenolic hydroxyl groups; while said gum is in solution, incorporating with said natural gum a potentially reactive synthetic resinous product, incorporating an abrasive granular material therewith, pressing the composite mass to a predetermined shape and size and heating to harden the resin and form a.

relatively strong abrasive implement.

42. An abras ve implement comprising a granular abrasive materialand a binder consisting of a natural m of plant origin containing free phenolic hydroxyl groups .and a potentially reactive synthetic resin said binder being hardened to a hard set infusible state.

43. An abrasive implement comprising a granular abrasive material and a binder consisting of a natural m of plant origin containing free phenohc hydroxyl groups and a potentially reactive phenol-aldehyde resinous condensation product, said binder being hardened to a hard set infusible state.

44. An abrasive implement comprising a granular abrasive material and a binder consisting of a natural gum of plant origin containing free phenolic hydroxyl .grou s and a otentially reactive polybasic aci -polyhysric alcohol condensation product, said binder being hardened to a'hard set infusible state.

45. An abrasive implement comprising a granular abrasive material and a binder consisting of gum accroides, a phenolic body and an aldehyde reacted to a hard set infusible state.

Signed at Philadelphia, in the county of Philadelpiha and State of Pennsylvania, thisird day of November A. D. 1932.

twenty-t EMIL E. NOVOTNY. 

